Wind tunnel for flight of models



July 5 1927.

Y 1,635,038 E. N. FALEs WIND TUNNEL FOR FLIGHT OF MODELS y Filed Abril18. 1922 2 sheets-sheet 1 Y B'\ a g2 1 fn W /N l N IU. .2

N T2 l s July 5, 1927. E. N FALES WIND TUNNEL FOR FLIGHT 0F MODELS FiledAvril 18. 1922 2 Sheets-Sheet -LNH a Patented July 45, 1927. u1,635,038l

UNITED STATES PATENT OFFICE.

ELISHA. NaFALES, F DAYTON; OHIO.

WIND TUNNEL FOR FLIGHT 0F MODELS.

Application led April 18, 1922. Serial No. 555,366.

This invention relates to improvements in 14; which is pivotallyconnected to a bracket wind tunnels whereby the free flight of airl5,mounted on the base 10, by means of a plane models may be obtainedtherein and pin 16. Metallic bands 17 embracing the the flightcharacteristics of the models obwind tunnel Aare connected to truss rods18 served. Which strengthen and support the wind tun- If a model of anairplane is built to scale nel throughout its length. The forward andproperly balanced it should be able to end of the truss rods areattached to Athe -c glide in a manner analogous to the full size forwardband 17 and connected to an elevatmachine. A current of air directeduping screw 18 by means of a ball and socket 1o wardlyat the glidingangle should support joint 19. The screw 18 passes through a the modelat a fixed point so that its propnut 20 into a casing 21 which may restupon erites may be observed. The behavior of the -loon the model underthese circumstances is simicasing 22 attached to the base 10 and conlarto the case of soaring birds which natunected to the wind tunnel by aflexible rally choose a place where the wind has an sleeve 23.

upward iow and then adjust their wings to It is necessary to adjust boththe angua gliding angle, such that in cahn air they larity of the windtunnel and the air vewould glide downward in a direction and at locity,since in a tunnel with parallel walls a speed equal and contrary to theupwardly the position of the model along the tunnel inclined a1rcurrent. The result is that the axis does not determine the velocity asis the soaring bird may remain motionless in space. case in a conicaltunnel.

The speed of the air in the wind tunnel thus To adjust the angularity ofthe wind tuninclined may be varied until the model is nel the nut 20 isturned to raise or lower the just supported; or the wind tunnel maybeWind tunnel about the pivot in 16. The air 25 so formed' that thevelocity differs along its speed in the tunnel may be a justed by varyjlength. In the latter case the airplane will ing the speed of themotor11.

move one way or the other until the air ve- VIn Figure 2 a frame 25supports a cylinlocity is just suflieient to support its weight, dricalwind tunnel 26 and the fan motor 27 and the position ofthe model in thetunnel vThe frame is provided near one end with 30 will ali'ord ameasure of the coeiiicient of lift, lugs 28 which are pivotally mountedin the because the weight of the model is known as yoke shaped upper endof a base or pedeswell as the air velocity at the point in questal 29.An elevating screw 30 engaging a tion. j nut 31 is Yconnected totheframe 25 by a ball In order to produce the conditions above and socketjoint. The lower end of the eledescribed a wind tunnel or a portionthereof, vating screw 30 is received within a casing according to myinvention, is pivoted on a 32. During the angular adjustment of thehorizontal axis in such manner that the air wind tunnel the motor 27moves therewith current may be caused to flow upwardly at so that thefan may be mounted directly any suitable angle. within the main body ofthe wind tunnel, as The invention is hereinafter described in shown. j l

In Figure 3 a conicalwind tunnel 34 and a fan motor 35 are mounted on aframe 36 similar to the frame 25 of Figure 2. An elevating screw and nut37, 38 are also conconnection with the accompanying drawings, in which 1Figure 1 is a side elevation of one embodiment of the invention.

form thereof. nel and -frame as described in connection Figure V3 is aside elevation of the invenwith Figures 1 and 2. The air velocity intion as applied to aconical tunnel. this wind tunnel will vary along thelength Figure 4 is a side elevation of a wind tunthereof owing to thegraduated expansion of nel having a pivoted portion in which free thesectional-area of the cone. The airilight may take place. plane modelwill adjust its position along In Figure 1, the number 10 designates athe conical wind tunnel until the air velocity base supporting the motor11 which drives at a section is just suiclent-to support its the fan 12located at one end of a wind tunweight. c nel 13.` The latter isprovided with a yoke i In Figure 4 a wind tunnel 40, having an The fan12 is located within a c Figure 2 is a side elevationof a modifiednected to the forward end of the wind tunexperimental chamber 41 andbell mouth 42 is associated with an auxiliary portion or wind tunnel inwhich free flight may be obtained. The auxiliary portion 43 is pro videdwith a iiexible end.44 which is adapted to fit tightly within thechamber or throat 41. Beams 45 support the auxiliary wind tunnel bymeans of spaced bands 46 embracing the body thereof and attached to thebeams. The beams 45 are pivotally connected at one end to a bracket 47attached to a vertical framework 48. The cable 49 of a hoist or Windlass50 is connected to the forward end of the auxiliary wind tunnel for thepurpose of changing the angular posit-ion thereof. A motor driven fan orpropeller (not shown) exhausts the air from the main wind tunnel in awell known manner and causes a flow through the tiltable por-v tion 43.The sides of the latter ldiverge toward the fan at a small angle so thatthe air How always ills this conical passageway. Glass doors or windows5l placed in the sides of the auxiliary tunnel permit observation of theinterior of the tunnel and access thereto. A light 52 brilliantlyilluminates the throat and interior of thc auxiliary wind tunnel.

4The small model of an airplane is introduced into the Wind tunnelportion 43, and the angle of the tunnel, air velocity therein, and thebalance of the model are varied until free flight is successfullyattained. In a conical Wind tunnel the proper velocity is automaticallysought by the model which will travel downstream or up-stream to seekthe velocity corresponding to its angle of incidence, thereby takingcare of one of the variable factors recited above. The study of theHight of free flying models becomes, as a result of this invention,alaboratory proposition oti'ering valuable information to the aircraftdesigner.

I claim:-

1. In combination a pivoted wind tunnel lfor the aerodynamic testing offreely suspended aerial models, and means for adjusting the angularposition thereof.

2. In combination a pivoted wind tunnel for the aerodynamic testing offreely suspended aerial models, having a variable speed fan adapted tovarv the air velocity therein, and means for adjusting the angularposition of the wind tunnel so as to di rect the air ow upwardly.

3. The combination with a wind tunnel for the aerodynamic testing -offreely suspended aerial models, of means for changing the angularposition thereof to direct the air flow upwardly at the proper angle toobtain the free flight of airplane models therein.:

4. The combination with a conical 'Wind tunnel for the aerodynamictesting of freely suspended aerial models, ol" means for changing theangular position thereof to direct the air How upwardly at such an anglethat the airplane model when placed therein is sustained in free llightat a section of said tunnel having the proper air velocity.

5. The combination with a wind tunnel for the aerodynamic testing offreely suspended aerial models, having an auxiliary portion in pivotedrelation thereto, llexible devices therebetween connecting the channelsthereof in continuous relation, and means for adjusting the angularrelation between said wind tunnel and auxiliary portion.

o. In combination with a conical wind tunnel for aerodynamic testing ofaerial models, means for inducing an air current therethrough, means forchanging the angu.

lar position of said wind tunnel to direct the air liow upwardly at suchan angle that the airplane niodvl therein is Sustained in free iight ata section of the wind tunnel having the proper air velocityanddirection.

7. In combination in a device for aerodynamic testing of aerial models,a wind tunnel, an exhauster fan, said wind tunnel having a substantiallyconical inner bore with its larger diameter toward said exhauster fan.

8. In combination in a device for aerodynamic testing of aerial models,a wind tunnel, an exhauster fan, said ,wind tunnel having asubstantially conical inner here with its larger diameter toward saidexhauster fan, and means for augularly adjusting said Wind tunnel.

9. In combination in a device for aerodynamic testing of aerial models,a wind tunnel, an eXhauster fan, said wind tunnel having a substantiallyconical inner bore with its larger diameter toward said exhauster fan,means for angularly adjusting said wind tunnel, and observation windowsthrough the sides of said wind tunnel.

10. In combination in a device for aerodynamic testing of aerial models,a wind tunnel, an exhauster fan, said wind tunnel having a substantiallyconical inner bore with its larger diameter toward said eX- hauster fan,inlet end of said wind tunnel being flared to prevent Vformation ofeddies in the air currents entering said tunnel.

In testimony whereof I afi'ix my signature.

ELISHA N. FALES.

